Folate intake and the risk of oral cavity and pharyngeal cancer: a pooled analysis within the International Head and Neck Cancer Epidemiology Consortium.

There are suggestions of an inverse association between folate intake and serum folate levels and the risk of oral cavity and pharyngeal cancers (OPCs), but most studies are limited in sample size, with only few reporting information on the source of dietary folate. Our study aims to investigate the association between folate intake and the risk of OPC within the International Head and Neck Cancer Epidemiology (INHANCE) Consortium. We analyzed pooled individual-level data from ten case-control studies participating in the INHANCE consortium, including 5,127 cases and 13,249 controls. Odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were estimated for the associations between total folate intake (natural, fortification and supplementation) and natural folate only, and OPC risk. We found an inverse association between total folate intake and overall OPC risk (the adjusted OR for the highest vs. the lowest quintile was 0.65, 95% CI: 0.43-0.99), with a stronger association for oral cavity (OR = 0.57, 95% CI: 0.43-0.75). A similar inverse association, though somewhat weaker, was observed for folate intake from natural sources only in oral cavity cancer (OR = 0.64, 95% CI: 0.45-0.91). The highest OPC risk was observed in heavy alcohol drinkers with low folate intake as compared to never/light drinkers with high folate (OR = 4.05, 95% CI: 3.43-4.79); the attributable proportion (AP) owing to interaction was 11.1% (95% CI: 1.4-20.8%). Lastly, we reported an OR of 2.73 (95% CI:2.34-3.19) for those ever tobacco users with low folate intake, compared with nevere tobacco users and high folate intake (AP of interaction =10.6%, 95% CI: 0.41-20.8%). Our project of a large pool of case-control studies supports a protective effect of total folate intake on OPC risk.

Coffee and tea intake and risk of head and neck cancer: pooled analysis in the international head and neck cancer epidemiology consortium.

BACKGROUND: Only a few studies have explored the relation between coffee and tea intake and head and neck cancers, with inconsistent results. METHODS: We pooled individual-level data from nine case-control studies of head and neck cancers, including 5,139 cases and 9,028 controls. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI), adjusting for potential confounders. RESULTS: Caffeinated coffee intake was inversely related with the risk of cancer of the oral cavity and pharynx: the ORs were 0.96 (95% CI, 0.94-0.98) for an increment of 1 cup per day and 0.61 (95% CI, 0.47-0.80) in drinkers of >4 cups per day versus nondrinkers. This latter estimate was consistent for different anatomic sites (OR, 0.46; 95% CI, 0.30-0.71 for oral cavity; OR, 0.58; 95% CI, 0.41-0.82 for oropharynx/hypopharynx; and OR, 0.61; 95% CI, 0.37-1.01 for oral cavity/pharynx not otherwise specified) and across strata of selected covariates. No association of caffeinated coffee drinking was found with laryngeal cancer (OR, 0.96; 95% CI, 0.64-1.45 in drinkers of >4 cups per day versus nondrinkers). Data on decaffeinated coffee were too sparse for detailed analysis, but indicated no increased risk. Tea intake was not associated with head and neck cancer risk (OR, 0.99; 95% CI, 0.89-1.11 for drinkers versus nondrinkers). CONCLUSIONS: This pooled analysis of case-control studies supports the hypothesis of an inverse association between caffeinated coffee drinking and risk of cancer of the oral cavity and pharynx. IMPACT: Given widespread use of coffee and the relatively high incidence and low survival of head and neck cancers, the observed inverse association may have appreciable public health relevance.

Citrus fruit and cancer risk in a network of case-control studies.

BACKGROUND: Citrus fruit has shown a favorable effect against various cancers. To better understand their role in cancer risk, we analyzed data from a series of case-control studies conducted in Italy and Switzerland. PATIENTS AND METHODS: The studies included 955 patients with oral and pharyngeal cancer, 395 with esophageal, 999 with stomach, 3,634 with large bowel, 527 with laryngeal, 2,900 with breast, 454 with endometrial, 1,031 with ovarian, 1,294 with prostate, and 767 with renal cell cancer. All cancers were incident and histologically confirmed. Controls were admitted to the same network of hospitals for acute, nonneoplastic conditions. Odds ratios (OR) were estimated by multiple logistic regression models, including terms for major identified confounding factors for each cancer site, and energy intake. RESULTS: The ORs for the highest versus lowest category of citrus fruit consumption were 0.47 (95% confidence interval, CI, 0.36-0.61) for oral and pharyngeal, 0.42 (95% CI, 0.25-0.70) for esophageal, 0.69 (95% CI, 0.52-0.92) for stomach, 0.82 (95% CI, 0.72-0.93) for colorectal, and 0.55 (95% CI, 0.37-0.83) for laryngeal cancer. No consistent association was found with breast, endometrial, ovarian, prostate, and renal cell cancer. CONCLUSIONS: Our findings indicate that citrus fruit has a protective role against cancers of the digestive and upper respiratory tract.

Onion and garlic use and human cancer.

BACKGROUND: Interest in the potential benefits of allium vegetables, in particular, onion (Allium cepa) and garlic (Allium sativum), has its origin in antiquity, but the details of these benefits are still open to discussion. OBJECTIVE: We investigated the role of allium vegetables in the etiology of various neoplasms. Previous data are scanty and are based mainly on Chinese studies. DESIGN: Using data from an integrated network of Italian and Swiss case-control studies, we analyzed the relation between frequency of onion and garlic use and cancer at several sites. We calculated odds ratios (ORs) by using multivariate logistic regression models that were adjusted for energy intake and other major covariates. RESULTS: Consumption of onions varied between 0-14 and 0-22 portions/wk among cases and controls, respectively. The multivariate ORs for the highest category of onion and garlic intake were, respectively, 0.16 and 0.61 for cancer of the oral cavity and pharynx, 0.12 and 0.43 for esophageal cancer, 0.44 and 0.74 for colorectal cancer, 0.17 and 0.56 for laryngeal cancer, 0.75 and 0.90 for breast cancer, 0.27 and 0.78 for ovarian cancer, 0.29 and 0.81 for prostate cancer, and 0.62 and 0.69 for renal cell cancer. CONCLUSIONS: This uniquely large data set from southern European populations shows an inverse association between the frequency of use of allium vegetables and the risk of several common cancers. Allium vegetables are a favorable correlate of cancer risk in Europe.

A pooled analysis of case-control studies of thyroid cancer: cigarette smoking and consumption of alcohol, coffee, and tea.

OBJECTIVE: To analyze the role of smoking, alcohol, coffee and tea in relation to thyroid cancer, we conducted a pooled analysis of 14 case-control studies conducted in the United States, Europe, and Asia. METHODS: The sample consisted of 2725 thyroid cancer cases (2247 females, 478 males) and 4776 controls (3699 females, 1077 males). Conditional logistic regression with stratification on study, age at diagnosis, and gender was used to compute odds ratios and 95% confidence intervals. RESULTS: Thyroid cancer risk was reduced in persons who had ever smoked. The relationship was more pronounced in current smokers (OR = 0.6, 95% CI = 0.6-0.7) than former smokers (OR = 0.9, 95% CI = 0.8-1.1). There were significant trends of reduced risk with greater duration and frequency of smoking. For consumption of wine and beer, there was a significant trend of decreasing thyroid cancer risk (p = 0.02) that was not maintained after adjustment for current smoking (p = 0.12). Thyroid cancer risk was not associated with consumption of coffee or tea. These findings were consistent in both gender-specific and histology-specific (papillary and follicular) analyses. CONCLUSIONS: Pooled analyses of these geographically diverse case-control data indicate a reduced thyroid cancer risk associated with current smoking. A reduced risk associated with alcohol was eliminated after adjustment for smoking, and caffeinated beverages did not alter thyroid cancer risk.

Coffee and tea intake and risk of oral, pharyngeal and esophageal cancer.

The relation between coffee, decaffeinated coffee, tea and oral/pharyngeal, and esophageal cancer risk is inadequately quantified. Data were derived from hospital-based case-control studies conducted in Italy and Switzerland. The study on oral/pharyngeal cancer included 749 cases and 1772 controls, and that of esophageal cancer 395 cases and 1066 controls. Multivariate odds ratios (OR) and 95% confidence intervals (CI) were computed. The OR for >3 cups/day of coffee compared with

Fried potatoes and human cancer.

A considerable public concern about cancer risk from acrylamide-rich foods followed the announcement that high concentrations of acrylamide are found in fried potatoes and potato chips and, more generally, in starch-containing foods cooked at high temperatures. From a series of hospital-based case-control studies conducted in Italy and Switzerland between 1991 and 2000, we have analyzed the relation between intake of fried/baked potatoes and cancer risk. The cancer sites considered were oral cavity and pharynx (749 cases, 1772 controls), esophagus (395 cases, 1066 controls), larynx (527 cases, 1297 controls), large bowel (1225 colon and 728 rectum cases, 4154 controls), breast (2569 cases, 2588 controls) and ovary (1031 cases, 2411 controls). All cancer cases were incident and histologically confirmed. Controls were subjects admitted to the same network of hospitals of cases for acute, non-neoplastic conditions. All the odds ratios (OR) for the highest vs. the lowest tertile of intake ranged between 0.8-1.1. We found no evidence of interaction with age, gender, alcohol and tobacco use. Our data provide reassuring evidence for the lack of an important association between consumption of fried/baked potatoes and cancer risk.

n-3 polyunsaturated fatty acid intake and cancer risk in Italy and Switzerland.

Data from a series of case-control studies, conducted in Italy and Switzerland between 1991 and 2001, have been analyzed to evaluate the role of n-3 polyunsaturated fatty acid (PUFA) intake in the etiology of cancer of oral cavity and pharynx (736 cases, 1772 controls), esophagus (395 cases, 1066 controls), large bowel (1394 colon, 886 rectum, 4765 controls), breast (2900 cases, 3122 controls) and ovary (1031 cases, 2411 controls). Controls were patients admitted to hospital for acute, non-neoplastic conditions, unrelated to modifications in diet. The multivariate odds ratios (OR) for the highest quintile of n-3 PUFAs compared to the lowest one were 0.5 for oral and pharyngeal cancer, 0.5 for oesophageal cancer, 0.7 for colon cancer, 0.8 for rectal and breast cancer and 0.6 for ovarian cancer; the estimates and the trends in risk were significant for all cancer sites, excluding rectal and breast cancer. The estimates for an increase in n-3 PUFAs of 1 g/week were 0.70 for oral and pharyngeal cancer, 0.71 for oesophageal, 0.88 for colon, 0.91 for rectal, 0.90 for breast and 0.85 for ovarian cancer. All the estimates were statistically significant, excluding that for rectal cancer, and consistent across strata of age and gender. These results suggest that n-3 PUFAs decrease the risk of several cancers.

Food groups and laryngeal cancer risk: a case-control study from Italy and Switzerland.

Besides tobacco and alcohol, diet has been thought to be associated with laryngeal cancer risk. We thus analyzed the role of various food groups, as well as specific seasoning fats, in a case-control study conducted in Northern Italy and the Swiss Canton of Vaud from 1992 to 2000. Our study included 527 incident, histologically confirmed cases and 1,297 frequency-matched controls, selected among patients admitted to the same hospitals as cases for acute, nonneoplastic conditions, unrelated to smoking, alcohol consumption and long-term modifications of diet. The subjects' usual diet was investigated through a validated food frequency questionnaire, including 78 foods and beverages. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional multiple logistic regression models. After adjustment for major confounding factors, a significant trend of increasing risk was observed for eggs (OR = 1.7 for the highest compared to the lowest quintile), red meat (OR = 3.1), processed meat (OR = 1.7), fish (OR = 1.6) and sugars (OR = 1.6). Significant inverse associations were observed for pulses (OR = 0.7), raw vegetables (OR = 0.2), cooked vegetables (OR = 0.3), citrus fruit (OR = 0.6) and other fruit (OR = 0.5). In regard to seasoning fats, a significant reduction of cancer risk was observed for olive oil (OR = 0.4) and specific seed oils (OR = 0.6), while mixed seed oils were directly associated with laryngeal cancer risk (OR = 2.2). Our study suggests that increasing vegetables and fruit, decreasing meat consumption and perhaps substituting olive oil or specific seed oils for other types of seasoning lipids might help reduce laryngeal cancer risk.